The invention relates to a water jet ventilator or aerator for connection to a sanitary fitting particularly a water outflow valve or mixer, having a water inlet, a water outlet and devices for splitting up and mixing the inflowing water with drawn in air positioned between the water inlet and the water outlet.
Such water jet ventilators, also known as jet regulators, have a water inlet and a water outlet, as well as devices for splitting up the water flowing into the water jet ventilator positioned between the water inlet and the water outlet and which serve to mix the water with drawn in air. Water jet ventilators are nowadays widely used, because a ventilated or aerated water jet does not splash and allows a quiet inflow of water. In addition, e.g. for washing the hands, the water quantity can be reduced without this having a disadvantageous effect on the cleaning power.
The devices for splitting up and mixing the inflowing water with drawn in air normally operate in a number of stages. Firstly the inflowing water is split up by a device for producing single jets. For this purpose there are normally one or more superimposed perforated plates, the holes normally being staggered. Following this in the flow direction there is normally a free space or a chamber with the possibility of air access from below, so that here air can be drawn in according to the water jet pump principle. The individual jets are then split up in at least one splitting and mixing device following in the flow direction and are mixed with the drawn in air.
Considerable differences exist between conventional water jet ventilators particularly with respect to the devices for splitting up and mixing the individual jets with air. In many of these screen arrangements are provided for this purpose consisting of several fine, superimposed screens, through which the jet is split up and mixing with air is obtained. However, they tend to clog through calcification. To reduce the calcification problem devices have already been proposed which are free from such screens.
EP 151 998 discloses a screenless water jet ventilator which is provided below the individual jet production devices and the air chamber with several concentric, terraced devices for splitting up the individual jets and accompanied by a simultaneous mixing with air, to which are connected concentric guide channels, which serve to calm and stabilize the water/air mixture. The guide channels have common partitions formed by concentric sleeves, whose height increases from the inside to the outside and which are cross-sectionally constructed in the manner of step pyramids, i.e., they pass in terraced manner to either side. This geometrically relatively complex structure has only a limited calcification tendency and permits the formation of a uniformly ventilated full jet.
In a screenless jet regulator known from DE 196 42 055 the calcification problem is counteracted in that for splitting up the individual jets and the mixing thereof with air, in the flow direction is provided a multilayer arrangement of pins arranged transversely to the flow direction and which are parallel to one another. As a result intersections are avoided, which in conventional screen structures are favoured points for the accumulation of water and subsequent lime formation or calcification.
The problem of the invention is to further improve known water jet ventilators with regards to their calcification behavior.
According to the invention this problem is solved in that in a known water jet ventilator at least one component of the water jet ventilator coming into contact with water in the vicinity of the water outlet is provided at least in said water outlet area with a soft and/or water-repelling surface. The term water-repelling surface is in particular intended to cover those surfaces which as a result of external pressure are easily and in particular reversibly deformable, i.e. preferably elastic, flexible surfaces. Water-repelling in the sense of the invention is a property of a surface if, as a result of its chemical and/or physical characteristics and/or its structure is only wetted with difficulty by water, i.e. has a high inter-facial energy relative to water.
The invention is based on a solution fundamentally differing from the prior art, in that an attempt is not or not only made by means of a specific geometrical arrangement of components and/or their purpose-design shaping to increase the security against calcification, but instead to a particular extent surface characteristics of components are influenced, which are in particular located in the calcification-endangered area of the water outlet. If a water tap or the like is switched off, then normally residual water continues to adhere to components in the vicinity of the water outlet and slowly evaporates, so that normally a lime residue is left behind at the attachment point of the evaporated droplet. The resulting calcification more particularly occurs in the vicinity of the outlet end due to gravity and as a result said end can slowly clog or block.
According to the proposal of the invention at least the area of the outlet end is made lime-repelling in that at the endangered surfaces either water droplets do not adhere or only adhere to a limited extent or with a limited volume or their contact surface with the component is so small that only quasi-punctiform lime residues are left behind. As a function of the surface characteristics alternatively or additionally in the case of soft surfaces possibly deposited lime can be removed and detached by slight deformation or bending of the component surface. Thus, on the one hand calcification can be avoided or minimized from the outset and alternatively or additionally easier cleaning possibilities can be created for calcified elements in the vicinity of water outlets.
As the invention substantially relates to the surface characteristics of jet guidance elements and/or jet obstacles in the vicinity of the water outlet, the invention can be used with advantage in all water jet ventilators and optionally their geometry optimized with respect to calcification and/or other characteristics can be largely or completely retained. Preferably, the invention is implemented with screenless jet ventilators or regulators.
The invention can be implemented in different ways. Thus, it is e.g. possible for at least one of the particularly calcification-endangered components of said type to be made substantially completely from a soft and/or water-repelling material, particularly from a corresponding plastic. Components made from suitable solid material can generally be particularly inexpensively manufactured. The construction from solid material is particularly intended for those components which, as a result of their dimensioning and/or shaping have a certain shape stability and/or those which in the operation of the water jet ventilator have boundary surfaces substantially parallel to the flow direction, so that they are only moderately affected by the flowing water. Thus, the components, e.g. axial guidance elements, can be generally made from soft, particularly elastomeric plastic, such as silicone rubber or the like and in particular from thermoplastic elastomers. The thermoplastic elastomers e.g. include Santopren(copyright), a polymer based on polypropylene and EPDM (ethylene/propylene/diene terpolymer). It is also possible to use primarily water-repelling materials, such as polytetrafluoroethylene (PTFE) or silicones, such as silicone resins. In the case of a correspondingly thin construction they can also have an adequate softness or flexibility. In the case of components, whose calcification-reducing characteristics are essentially based on the surface softness, it must in particular be ensured that at least the area of the soft surface is manually accessible, so that any deposited lime can be manually removed by deformation of the components or can be chipped off. Particularly suitable are soft materials with a hardness between approximately 20 and approximately 80 Shore A and for solid material components hardnesses in the upper range, e.g. between 50 and 80 Shore A, particularly approximately 80 Shore A are preferred, so as to give the components a certain dimensional stability in spite of the desired flexibility.
It is also possible for at least one component, at least in the vicinity of the water outlet, to have a coating or covering of a soft and/or water-repellent material. This coating can be applied to a support, whose mechanical characteristics essentially determine the volume properties of the component, such as stiffness or the like, whilst the coating creates the desired surface characteristics. Particular preference is given to water-repellent coatings with hydrophobic plastics, e.g. silicone or polytetrafluoroethylene, which can be applied to the support structure e.g. by spraying, dipping or other suitable processes.
Primarily water-repellent coverings can be very thin and generally only insignificantly change the geometry of the support structure. Preferred coating thicknesses can here be less than 0.1 mm, particularly between approximately 1 and 10 xcexcm. In the case of a coating with a primarily soft material it is preferably ensured that the coating thickness is dimensioned in such a way that the coating is intrinsically movable, particularly compressible, in order to encourage the chipping off of lime residues by pressure on the coating. Coating thicknesses of more than 0.1 mm, particularly between 0.2 and 0.4 mm can be appropriate. As in the case of coatings the volume characteristic of the component, such as its stiffness, is essentially determined the support material, the material of the coating, whose hardness is appropriately between approximately 20 and approximately 80 Shore A, can be located in the lower part of this hardness range, e.g. between approximately 20 and approximately 50 Shore A. Even limited stripping forces are sufficient to bring about a deformation causing lime to be chipped off.
According to another embodiment, points, particularly edges of components located at the water outlet are provided with a thicker coating and/or are constructed in pointed or knife blade-like manner in the water outlet direction. On the one hand this improves the deformability and on the other brings about a good detachment of the water droplets. The coating thickness at these points can be up to 2 mm or more.
The advantages of the invention can also be utilized in that with the water jet ventilator is associated at least one component in the form of a flat or surface element through which there is a flow and positioned or positionable close to the water outlet and which has a soft and/or water-repellent surface. The flat element can be designed in such a way that it substantially covers the entire cross-section of the water outlet and forms a lower termination of the water jet ventilator, where preferably residual water collection takes place. Thus, further inwardly positioned components are better protected from the outset against lime accumulations, because residual water generally sticks to the furthest downwardly positioned parts. Simultaneously a protection of the inner components against mechanical damage is provided. The flat element can in particular be a grid or grating with randomly designed water outlets. It can in particular be a rectangular, diamond-shaped or honeycomb grating. Spiral or perforated disk-like flat elements are also possible. At least in the through-flow area, the flat element can be substantially completely made from soft and/or water-repellent material or can be coated with such a material.
Preferably the flat element is constructed as an insert detachably connectable to the water jet ventilator. A flat element can also be connected in fixed form to the water jet ventilator, e.g. molded into the same.
In preferred embodiments all components of the jet ventilator or regulator which come into contact with water, have water-repelling surface characteristics, at least those which also come into contact with air and where an evaporation of water can take place.